"Chemung" Formation, Parkhead Sandstone, Brallier Formation, and Harrell Shale

"Chemung" Formation - Predominantly marine beds characterized by gray to olive-green graywacke, siltstone, and shale; thickened ranges from 2,000 to 3,000 feet; Parkhead Sandstone - Gray to olive-green sandy shale, conglomeratic sandstone and graywacke; present in Washington County, identification uncertain in west; thickness averages 400 feet; Brallier Fomation - (Woodmont Shale of earlier reports). Medium to dark gray, laminated shale and siltstone; weathers to light olive-gray; grain size coarsens upward; thickness about 2,000 feet in west, about 1,7000 feet in east; and Harrell Shale - Dark gray laminated shale; absent in east where Brallier lies directly on Mahantango, Tully Limestone lies near base in west, in subsurface of Garrett County; total thickness in west 140 to 300 feet.
State Maryland
Name "Chemung" Formation, Parkhead Sandstone, Brallier Formation, and Harrell Shale
Geologic age Devonian
Lithologic constituents
Sedimentary > Clastic > Siltstone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone > Graywacke
Sedimentary > Clastic > Sandstonelocally conglomeratic
Sedimentary > Carbonate > Limestone
Comments Chemung, Parkhead, Brallier, and Harrell Formations formerly were designated as Jennings Formation.

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/


NGMDB product
Counties Allegany - Garrett - Washington